Boston (CNN) - A "heartbroken" Martha Coakley congratulated her Republican opponent Tuesday on his upset victory over her to fill the U.S. Senate seat held for decades by liberal Democrat Ted Kennedy.
In a subdued concession speech, Coakley, the Democratic Massachusetts attorney general, said she expected a tough assessment of her loss and lots of "Wednesday-morning quarterbacking" after losing a seat held by Democrats for more than 50 years.
"I am heartbroken at the result," Coakley said, later adding: "Although I am very disappointed, I always respect the voters' choice."
Coakley's defeat to Republican state Sen. Scott Brown was a major blow to Democrats, who now lose their super-majority control of the Senate to imperil President Barack Obama's domestic agenda.
In an unintentional symbol of the damage, the other Massachusetts senator, Democrat John Kerry, was on crutches as he stood on stage with Coakley.
Coakley thanked her supporters for what she called their "fierce determination."
Privately, Democratic sources have criticized Coakley for what they described as an ineffective campaign in a race she was expected to win easily.
No Republican had won a U.S. Senate race in Massachusetts since 1972, and Democrats control the governorship, both houses of the state legislature, and the state's entire congressional delegation.
Coakley said she called Brown to congratulate him, and that she received a call from Obama, who she said urged her to keep fighting for the people of Massachusetts.
She concluded by quoting the signature line of Ted Kennedy, who died of brain cancer last August, saying: "The work begins anew, the hope rises again, and the dream lives on."